Dale Steyn said he wanted to improve as a bowler after claiming his second successive ten-wicket haul as South Africa crushed New Zealand by an innings and 59 runs on the third day of the second and final Test against New Zealand at Centurion Park Sunday.

The 24-year-old has rocketed into the top 10 of the world Test bowling rankings but said he didn't believe he had yet "arrived" as a world-class bowler despite taking 71 wickets in his first 15 Tests.

The fast bowler, consistently bowling at more than 145kmh and making the ball swing away from right-handed batsmen, took a career-best six for 49 as New Zealand were shot out for 136 in their second innings.

His match figures of 10 for 91 were two runs better than his 10 for 93 in the first Test in Johannesburg, which South Africa won by 358 runs.

He was man of the match in both Tests and took the man of the series award.

"I'm just doing what I have to do," he said, "getting the ball in the right places and communicating well with my captain."

He gave credit to the support staff including the video analysts.

"The guys off the field prepare these things so we can see the strengths and weaknesses of our opponents. We have bowled to a plan."

Captain Graeme Smith said Steyn had bowled "superbly" but said the credit had to be shared with the rest of the bowlers.

"He's bowled at pace with good control and he's got the ball to swing. But the other guys have worked around him pretty well which has allowed him to come back at different times and strike. I like to know that he's hungry for more success."

Smith said South Africa had played "really good Test cricket" in winning a two-match series in Pakistan last month as well as hammering New Zealand.

New Zealand captain Daniel Vettori admitted that the series had been a tough start to his career as Test skipper.

"It doubles up after the performance we put up at the Wanderers. We thought we could come back and fight a little bit harder here but unfortunately we delivered a similarly inept performance."

Vettori said the bowling of Steyn and the batting partnerships between Hashim Amla and Jacques Kallis, who both scored two centuries in the series, had "set the two teams apart".

"We need to play more Test cricket," he said of a side that had only played two Test matches in more than a year leading up to the series.

"It's also got to come down to individuals, to increase skill levels and desire. We need to put performances together against quality opposition. We've got Bangladesh coming up next.

"If we go ahead and win those games it doesn't necessarily mean we've become a good Test team. We've got to put performances together against teams like Australia and South Africa, and England back home in our summer."

Injuries hampered the tourists with Shane Bond and Jacob Oram breaking down during the first Test and Craig Cumming playing no further part in the second Test after being struck by a Steyn bouncer.

"It's injuries in games that really hurt you. You can adapt when injuries happen before games but when things happen in games it's tough," said Vettori.

Only former captain Stephen Fleming, who made 54, and fast bowler Mark Gillespie, who took five wickets in an innings on debut, shone for an outclassed New Zealand team on Sunday.

Steyn started the New Zealand slide by dismissing both opening batsmen, Lou Vincent and Michael Papps, with his first nine deliveries of the innings. Both were out leg before but Vincent was unlucky as replays showed the ball would have missed leg stump.

Fleming and Scott Styris (29) put on 60 for the third wicket before New Zealand crumbled.

Earlier Amla completed his second successive century, while Gillespie took five for 136 but could not prevent South Africa from taking a 195-run first innings lead.

Final scoreboard on the third day of the second and final Test between South Africa and New Zealand at Centurion Park Sunday.